diff --git a/storage/myisam/mi_static.c b/storage/myisam/mi_static.c
index a43a099663bbc716e47d16241f92616f74e8ca8a..27485e101ff84d00ebe4ba7d745e3aae39cfe7f2 100644
--- a/storage/myisam/mi_static.c
+++ b/storage/myisam/mi_static.c
@@ -41,7 +41,6 @@ my_off_t myisam_max_temp_length= MAX_FILE_SIZE;
 ulong    myisam_bulk_insert_tree_size=8192*1024;
 ulong    myisam_data_pointer_size=4;
 ulonglong    myisam_mmap_size= SIZE_T_MAX, myisam_mmap_used= 0;
-pthread_mutex_t  THR_LOCK_myisam_mmap;
 
 static int always_valid(const char *filename __attribute__((unused)))
 {